Effect of Bose-Einstein statistics on two-particle azimuthal and rapidity correlations

The short-range effect in azimuthal and rapidity correlations can be explained within the independent cluster model taking into account the cluster transverse momentum and the Bose-effect (identical particle effect) in the single as well as the two-cluster term. Good agreement with data from Dubna, NAL and ISR is obtained. From the data we determine parameters related to the longitudinal and transverse dimensions of the clusters.     

Semiinclusive two-particle correlations and independent cluster emission at ISR energies

Semiinclusive two-particle correlations are calculated in the independent cluster emission model. The resulting semi-inclusive correlation functions ?₂ⁿ(y₁ = y₂ = 0) agree rather than well experimental data, esp. with respect to the multiplicity dependence. The average number of charged particles per cluster found from comparison with semiinclusive data is 2.5 charged particles per cluster, a value found earlier also from analysis of inclusive correlations.     

Diffusion and two-particle correlations

Fluctuation signals of the QCD phase transition in nuclear collisions can be dissipated due to diffusion. Diffusive modes in the standard formulation of relativistic hydrodynamics propagate with infinite speed, violating causality. We develop a causal diffusion equation study the dissipation of net-charge fluctuations. We find that causality restricts the extent to which diffusion can dissipate these fluctuations.     

Inclusive two-particle rapidity correlations at ISR energies and fireball production

ISR data on two-particle rapidity correlations in the region y₁ ≈ y₂ can be understood in terms of the multiperipheral fireball model and indicate an energy independent upper limit of the average fireball mass. The diffractive contribution to the fireball production leads to characteristic shapes of long range correlations. Data on long range rapidity correlations may be used to determine the fractions of non-diffractive and diffractive one- and two-fireball production.     

Quantum correlations in two-particle Anderson localization

We predict quantum correlations between noninteracting particles evolving simultaneously in a disordered medium. While the particle density follows the single-particle dynamics and exhibits Anderson localization, the two-particle correlation develops unique features that depend on the quantum statistics of the particles and their initial separation. On short time scales, the localization of one particle becomes dependent on whether or not the other particle is localized. On long time scales, the localized particles show oscillatory correlations within the localization length. These effects can be observed in Anderson localization of nonclassical light and ultracold atoms.     

Flow measurements via two-particle azimuthal correlations in Au + Au collisions at sqrt [s(NN)]=130 GeV

Two-particle azimuthal correlation functions are presented for charged hadrons produced in Au+Au collisions at the Relativistic Heavy Ion Collider (sqrt [s(NN)]=130 GeV). The measurements permit determination of elliptic flow without event-by-event estimation of the reaction plane. The extracted elliptic flow values (v2) show significant sensitivity to both the collision centrality and the transverse momenta of emitted hadrons, suggesting rapid thermalization and relatively strong velocity fields. When scaled by the eccentricity of the collision zone epsilon, the scaled elliptic flow shows little or no dependence on centrality for charged hadrons with relatively low p(T). A breakdown of this epsilon scaling is observed for charged hadrons with pT >1.0 GeV/c.     

Hydrodynamics: Fluctuating initial conditions and two-particle correlations

Event-by-event hydrodynamics (or hydrodynamics with fluctuating initial conditions) has been developed in the past few years. Here we discuss how it may help to understand the various structures observed in two-particle correlations.     

The influence of final state interaction on two-particle correlations in multiple production of particles and resonances

The structure of pair correlations of interacting particle moving with nearby velocities is analysed. A general formalism of the two-particle space-time density matrix, taking into account the space-time coherence of the production process, is developed. The influence of strong final state interaction on two-particle correlations in the case of the production of a systemresonance+particle is investigated in detail. It is shown that in the limit of small distances between the resonance and particle production points the effect of final state interaction is enhanced due to logarithmic singularity of the triangle diagram. Numerical estimates indicate that, in this limit, the effect of strong final state interaction becomes important even for two-pion correlations.     

Decomposition of multi-particle azimuthal correlations in Q-cumulant analysis

The method of Q-cumulants is a powerful tool for studying the fine details of azimuthal anisotropies in high energy nuclear collisions.This paper presents a new method,based on mathematical induction,to evaluate the analytical form of high-order Q-cumulants.The capability of this method is demonstrated via a toy model that uses the elliptic power distribution to simulate the anisotropic emission of particles,quantified in terms of Fourier flow harmonics v_n.The method can help in study...     

Centrality,azimuthal and rapidity dependence of two-particle transverse-momentum correlation in relativistic heavy ion collisions

The centrality, azimuthal and rapidity dependence of two-particle transverse-momentum correlations are studied for Au-Au collision at 200 GeV using RQMD （relativistic quantum molecular dynamics） with and without final hadron re-scattering models. The influences of the re-scattering effects on the measured correlations are discussed. The results are compared with those from current heavy ion experiments.     

Centrality, azimuthal and rapidity dependence of two-particle transverse-momentum correlation in relativistic heavy ion collisions

The centrality, azimuthal and rapidity dependence of two-particle transverse-momentum correlations are studied for Au-Au collision at 200 GeV using RQMD (relativistic quantum molecular dynamics) with and without final hadron re-scattering models. The influences of the re-scattering effects on the measured correlations are discussed. The results are compared with those from current heavy ion experiments.     

On azimuthal angular correlations of jets in electron-positron annihilation

QCD is used to study the azimuthal angular dependence of jet distribution produced in electron-positron annihilation. Results are compared with those of a scalar colored gluon theory.     

Multiparticle azimuthal correlations of negative pions in nucleus-nucleus collisions

Multiparticle azimuthal correlations of ?? ^? mesons have been studied in dC, HeC, CC, CNe, MgMg, (d, He)Ta, CCu, CTa, and OPb collisions at momentum of 4.2, 4.5 GeV/c per nucleon within the standard transverse momentum analysis method of P. Danielewicz and G. Odyniec. The data were obtained by SKM-200-GIBS and Propane Bubble Chamber Collaborations of JINR. The axis has been selected in the phase space and with respect to this axis ?? ^? meson correlations were observed. The values of the coefficient of the correlations linearly depend on the mass numbers of projectile (A _P ) and target (A _T ) nuclei. The Quark-Gluon String Model satisfactorily describes the experimental results.     

Multiparticle azimuthal correlations in central nucleus-nucleus collisions at high energy

Multiparticle azimuthal correlations in central nucleus-nucleus collisions at high energy are described by a simple formula.The calculated results are in agreement with the experimental data of carbon and oxygen induced interactions at Dubna energy.The comparison between the calculated results and experimental data shows that particles are emitted isotropically in the rest frame of the emission sources,and the emission sources have movements in momentum space.     

Relativistic effects in bound two-particle systems

The predictions of relativistic Schrödinger theory (RST) for the relativistic effects in helium-like ions with high nuclear charge ( -80) are elaborated in the electrostatic approximation (i.e. neglection of the magnetic interactions). The corresponding RST results are found to meet with the experimental data and with the predictions of other theoretical approaches, provided an estimate of the (neglected) magnetic effects is taken into account. This suggests to carry through high-precision calculations (including the magnetic forces) in order to further test the physical significance of RST.Received: 28 August 2003, Published online: 20 April 2004PACS: 03.65.Pm Relativistic wave equations - 03.65.Ge Solutions of wave equations: bound states - 03.65.Ud Entanglement and quantum nonlocality (e.g. EPR paradox, Bells inequalities, GHZ states, etc.)     

Identical particle effect in azimuthal correlations at small rapidity separation

The difference of the short range effect observed in azimuthal correlations of like and unlike particle pairs is interpreted as due to an identical and unidentical boson effect, resp., in the decay of clusters produced in the central region of hadron hadron collisions.     

Multiparticle azimuthal correlations in central nucleus-nucleus collisions at high energy

Multiparticle azimuthal correlations in central nucleus-nucleus collisions at high energy are described by a simple formula. The calculated results are in agreement with the experimental data of carbon and oxygen induced interactions at Dubna energy. The comparison between the calculated results and experimental data shows that particles are emitted isotropically in the rest frame of the emission sources, and the emission sources have movements in momentum space.